Vorras Antibot

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1.0 100% FREE Freeware    
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Vorras Antibot is an image generation program that will help you prevent automatic form submission by robots.




Vorras Antibot is an image generation program that will help you prevent automatic form submission by robots.
If your web site is being overwhelmed with spam, automatic registrations, automatic forum or classified ad submissions etc., Vorras Antibot can solve this problem by introducing a picture in your HTML forms that only a human can recognize.

How does it work?

Vorras Antibot generates a random sequence of alphanumeric characters and a picture in PNG format that shows this sequence. It returns the filename of the picture and the sequence in encrypted (hashed) format.

The filename and encrypted sequence can then be stored in your HTML form. The user who attempts to fill out the form has to look at the picture and type in the sequence he sees.

When the form is submitted the sequence the user typed in is encrypted as well (hashed) and compared to the original sequence. If the sequences match the user passes the test, else it is necessary to re-try.

Vorras Antibot uses pre-existing PNG files to form the character sequence in PNG format. These files are graphic files of alphanumeric characters in PNG format, and are provided when you download Vorras Antibot. If you want to change the existing PNG files you can replace with your own as follows:

■ Use any graphics package to create png files for all letters and numbers and name them as a.png, b.png,..., 0.png, 1.png, ...
■ Upload them on your server and place them in the data subdirectory inside the Vorras Antibot directory.
■ Run the parseidat.py script. This will generate the intermediate format files a.dat, b.dat etc. necessary to run Vorras Antibot.

Please note that Vorras Antibot requires some scripting knowledge to be incorporated in your CGI scripts.

Here are some key features of "Vorras Antibot":

■ The images are unique and are generated dynamically. This is not a script showing pre-made pictures. Instead Vorras Antibot randomly selects a few alphanumeric characters and produces on-the-fly images that place these characters in an image including some noise.
■ Uses NIST's secure hash algorithm, known as SHA, producing 160 bits of encrypted data.
■ Software written in Python and is portable across many platforms, including most versions of UNIX and Windows.
■ The number of characters shown can be configured. As a general guideline, 5-8 characters are considered enough to provide adequate security.
■ We provide a set of PNGs that form the character set used. However the software can work with any PNG files of your choice. The given PNG are combined to form a dynamic image that includes random noise to confuse character recognition software.
■ Vorras Antibot distorts the image to make it resistant to pattern recognition algorithms.


■ Python 2.0 or higher installed
Last updated on March 17th, 2007
Vorras Antibot

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